This invention relates to a multiway valve for switching the fluid flow of a pressure medium. Especially, the present invention relates to a multiway valve with a valve spool slidingly disposed inside a valve hole which is sealed by at least one cap element.
A multiway valve is known from DE 197 06 059 A1. The multiway valve comprises a valve hole lengthwise disposed inside the valve housing in which a valve spool is slidingly operated. The valve housing has five outer ports which are connected with the inner valve hole. The fluid flow through the multiway valve depends on the axial position of the valve spool relative to the valve hole. For example, the two-position multiway valve provides in one switching position a supply of a connected fluid apparatus. The other switching position of the valve spool provides an ejecting of said apparatus.
For moving the valve spool in an axial manner in order to control the fluid flow through the valve one end of the valve spool is formed as a piston. The piston works together with cylindrical drive chambers integrated into the valve housing at the end of the valve hole so that the switching position of the valve spool is controllable by air pressure. A return spring disposed on the opposite side of the valve spool""s operating piston forces the valve spool back to its normal position.
A known three-position multiway valve differs from said two-position multiway valve in a manner that one spring is disposed at each side of the valve spool in order to centre the valve spool in the third position. Thus this three-position multiway valve providesxe2x80x94for examplexe2x80x94in one switching position a supply of a connected fluid apparatus. The other switching position of the valve spool provides an ejecting of said apparatus. In the neutral switching position the multiway valve seals off the fluid flow through the valve housing.
In order to seal the openings of the valve hole on both ends of the valve housing a respective cap element is fixed to the valve housing. The fixing means are several screws which are screwed into the valve housing parallel to the axis of the valve hole. To connect the multiway valve on a support element, e.g. a fluid manifold, further fixing means are needed.
It is the aim of the present invention to provide an integrated fixing solution for parts of a multiway valve.
This aim is obtained by a multiway valve wherein the cap element which seals the valve hole in the valve housing comprises at least one through bore or opening which is substantially disposed in a right angle to the axis of the valve hole in the mounted state of the cap element. Said through bore corresponds with a second through bore in the valve housing and also with a bore in a tight-fitting support element in order to fix the cap element on the valve housing and to fix the valve housing on the support element by the same fixing means.
Thus the present invention provides an integrated fixing solution for parts of a multiway valve which reduce the valve size. It is not necessary to fix a cap element by separate fixing means. The invention also reduces the time for mounting the multiway valve.
Preferably, the fixing means are at least one screw which is screwed into the bore of a tight-fitting support element. It is also possible to use other suitable fixing means, like bolts or rivets. It might be favourable when the fixing means comprise further screws which are disposed on at least one side of the central screw in order to fix the valve housing on the same or a further support element.
The support element can be a fluid manifold of a valve bank for connecting the valve housing with supplying and/or ejecting channels. It is also possible that the support element is an upper port module for connecting the valve housing with pilot valves. Moreover, an additional linking part to the support element might be disposed next to the valve housing fixed by the fixing means. In one preferred embodiment the multiway valve comprises two drive chambers with corresponding pistons which are disposed on both ends of the valve spool in order to provide a bi-stable two-position valve function. In another preferred embodiment two return springs and two pistons are disposed on each end of the valve spool which correspond with respective drive chambers in order to provide a mono-stable three-position valve function. Moreover, the present invention is applicable in further embodiments of a multiway valve which realise various valve functions. Especially, the present invention is applicable in a multiway valve with a solenoid as drive unit for the valve spool.
It might be favourable when the spring chamber has the same form as the drive chamber so that the return spring is interchangeable by a piston in order to change the valve function. Referring to the form of the corresponding cap element, its outer diameter is adapted to the inner diameter of the drive chamber.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the enclosed drawings.